TITLE: GCN CIRCULAR NUMBER: 11849 SUBJECT: GRB 110328A / Swift J164449.3+573451 DATE: 11/03/31 11:03:35 GMT FROM: Guy Pooley at MRAO, Cambridge, UK Guy Pooley (University of Cambridge) reports: The unusual source GRB 110328A / Swift J164449.3+573451 (GCNs 11823, 11824) was observed with the AMI large array at MRAO, Cambridge (UK) on 2011 Mar 31 over a frequency band from 13.5 to 17.25 GHz. The first observation ran from 02h07m to 08h06m UT; the weather conditions were poor. This observation started 2d13h after the first BAT trigger. The source reported in GCNs 11836, 11848 was detected with a mean flux density of 2.95 +- 0.30 mJy. Analysis of the data in 4 equal time divisions shows a steady increase (2.25, 2.48, 2.56, 3.46 mJy), and a spectral analysis shows a rising spectrum. A second observation from 09h01m to 10h17m UT gives a mean flux density of 2.75 +- 0.30 mJy and also suggests a rising spectrum. This message is quotable in publications.